1. Field of the Invention
The present invention pertains to a method of solids waste disposal by injecting slurries of particulate solids into subterranean formations through disposal wells by disaggregating the formation to accommodate a relatively large volume of such solids.
2. Background
The disposal of certain solids materials including earth materials such as drill cuttings and the like continues to be a vexing problem. Certain methods for disposing of slurries of particulate solids nave been proposed, including the methods described in U.S. patent application Ser. No. 07/910,381, filed Jul. 8, 1992 to Thomas K. Perkins, and U.S. Pat. No. 5,314,265 issued May 24, 1994 to Thomas K. Perkins, et al, both assigned to Atlantic Richfield Company. The methods described in the above-mentioned patent applications take into consideration that an earth formation may be hydraulically fractured and the fracture extended radially away from a wellbore and wherein the fracture serves as a storage space for particulate solids while the slurry carrier liquid leaks off through the fracture into the formation itself. Generally, the amount of solids material that may be disposed of in this manner is somewhat limited by the ability to extend the hydraulic fracture and to prevent premature build-up of a "filter cake" or the solids materials on the fracture faces which eventually prevents further injection of the disposal slurry. The techniques described in the above-mentioned applications deal with this problem. However, the formation characteristics of which the inventions described in these applications take advantage are not always available at disposal sites and the cost of transporting the material to be disposed of to preferred sites can be prohibitive.
Certain subterranean formations which have relatively low compressive stresses and sufficient porosity may not actually undergo the classic hydraulic fracture phenomena when fluids are injected under high pressure into such formations. In this regard, the present invention provides a method for disposing of relatively large volumes of slurried particulate solids wastes in formations which are relatively porous wherein the porosity of the formation may be taken advantage of in order to dispose of larger amounts of solids materials than may be disposed of by creating conventional hydraulically induced fractures.